Proper abdominal strength is required to help maintain normal trunk posture and function as well as to prevent injury, particularly to the lower back. A variety of exercises can be utilized to strengthen the abdominal muscles. Such exercises include, but are not limited to: conventional sit ups, crunches (partial sit ups), leg raises lying supine (with knees bent or straight), torso twists, hanging leg raises, pelvic tilts, kneeling crunches using cable resistance, exercises using abdominal sit up machines, etc.
In the process of abdominal conditioning, it is desirable for the individual to do exercises appropriate for their level of abdominal strength and coordination to prevent injury and to facilitate optimal strengthening. There exist a number of prior art devices which a user may use to assist with exercising his or her abdominal muscles.
For example, U.S. Pat. No. 5,755,647 to Watnik discloses an exercise appliance which includes a structure presenting a resiliently yieldable contact surface having a contour suitably sized and shaped to be at least partially fittable in the space formed between a support surface and a static lordotic curve of a lumbar back of an individual. The appliance may also be provided with means for providing feedback in response to compression of the appliance.
Other examples of prior art apparatus relating to abdominal fitness include U.S. Pat. Nos. 6,648,838, 6,117,095, 6,019,738, 5,785,669, 5,515,865, 5,304,109, 4,905,990, 4,759,543, and 3,325,799, U.S. Patent Application Publications No. 2005/0043660 and No. 2001/0020143, and PCT Publications No. WO 2001/26506 and No. WO 2004/002313.
Although there exist devices designed to strengthen the abdominal muscles, and many exercises designed to do the same, the inventor has determined that there is a need for accurate abdominal muscle strength testing which is vital for appropriate exercise recommendations and is also useful for monitoring rehabilitation, research and the like.